Kindermann, Markus Karl; Kowski, Klaus; Muchall, Heidi M.; Rademacher, Paul:
Gas-phase thermolysis of pyrazolines. 2. Electronic structure and gas-phase thermolysis of 4,5-dihydro-3H-pyrazoles studied by photoelectron spectroscopy, semiempirical quantum-chemical calculations, and flash vacuum pyrolysis.
1993
In: Chemische Berichte (Chem.Ber.), Jg. 126 (1993), Heft 12, S. 2675 - 2681
Artikel/Aufsatz in Zeitschrift / Fach: Chemie
Titel:
Gas-phase thermolysis of pyrazolines. 2. Electronic structure and gas-phase thermolysis of 4,5-dihydro-3H-pyrazoles studied by photoelectron spectroscopy, semiempirical quantum-chemical calculations, and flash vacuum pyrolysis.
Autor(in):
Kindermann, Markus Karl; Kowski, Klaus im Online-Personal- und -Vorlesungsverzeichnis LSF anzeigen; Muchall, Heidi M.; Rademacher, Paul im Online-Personal- und -Vorlesungsverzeichnis LSF anzeigen
Erscheinungsjahr:
1993
Erschienen in:
Chemische Berichte (Chem.Ber.), Jg. 126 (1993), Heft 12, S. 2675 - 2681
ISSN:

Abstract:

The PE spectra of the 4,5-dihydro-3H-pyrazoles (I; X,R given:CH2,H; CHOH,Me), of 2,5-dihydro-1,3,4-oxadiazole (II), and 2,5-dihydro-1,3,4-thidiazole (III) have been recorded. Based on HAM/3, MNDO, AM1, and PM3 calcns., the ionization potentials have been assigned to MOs. The gas-phase thermolyses of I, II, and III have been studied by PE-controlled gas anal. Extrusion of mol. nitrogen leads to reactive species which cyclize to three-membered rings of different stability. At higher temps. and in flash vacuum pyrolysis, consecutive reactions may lead to smaller acyclic mols. The cyclopropanol (IV), obtained by denitrogenation of I(X=CHOH,R=Me), is thermally rather stable. The PE spectrum of IV has been recorded and analyzed.